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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 18 Abstracts search results
Document:
SP143-07
Date:
May 1, 1994
Author(s):
A. Carpinteri, S. Valente, G. Ferrara, and L. Imperato
Publication:
Symposium Papers
Volume:
143
Abstract:
Two small-scale 1:40 models of a gravity dam are subjected to equivalent hydraulic and weight loading. An initial notch in the upstream wall propagates during the loading process toward the foundation. Crack mouth opening control is performed, and the load-versus-CMOD diagram is plotted. A numerical simulation of the experiments is carried out using a cohesive fracture model in mixed mode condition. The structural behavior of the models and the crack trajectories are reproduced by the finite element idealization in a satisfactory way. The experiments described in this paper, while adopting the physical modeling techniques for civil structures, would be better defined as an example of the application of an experimental technique for assessing structural and material performance of concrete rather than rigorous physical modeling.
DOI:
10.14359/4582
SP143-09
R. Y. Miao and W. H. Yang
The interface confining stress between steel tube and core concrete is an important problem in the analysis of the behavior of concrete-filled steel tubes. However, no satisfactory experimental method to measure the interface stress directly has been developed because of the peculiar geometry of concrete-filled steel tubes. In this study, the significance of measuring interface stress is discussed, and the use of hydraulic analogy, or analogous hydraulically loaded control specimens, is introduced. In this paper, the fundamental mechanism, instrumentation, and procedure of hydraulic analogy will be described in detail together with examples.
10.14359/4583
SP143-10
M. Wecharatana and A. P. Ranasinghe
The break-off test is a recently developed nondestructive test for concrete. Although many experimental investigations have been carried out on this test, no in-depth theoretical evaluation has been done. In this study, the behavior of the break-off test specimen is investigated, and the theoretical basis of the test is explored. Based on linear elastic fracture mechanics, a model to predict the strength-manometer reading relationship of the test is proposed and compared with experimental results with good correlation. It was found that the ACI recommendation on the modulus of rupture (MOR) may be very conservative for certain members. The MOR of a rectangular beam is different from that observed from a circular cross section, such as the break-off test specimen. New MOR values are suggested for small rectangular beams and members with circular cross sections.
10.14359/4584
SP143-11
A. M. Hammad and M. A. Issa
Fracture surfaces of concrete and mortar are irregular, tortuous, and stochastic in nature. To describe irregular and rough surfaces, quantitative fractographic parameters such as profile and surface roughness, fractal dimension, Fourier spectral analysis, etc., are often used. A fractal description of fracture surfaces of concrete and mortar by utilizing a new nondestructive technique, introduced by the authors, will be presented in this paper. Compact tension-fractured concrete specimens with a compressive strength of 46.8 MPa and a maximum aggregate size of 37.5 mm and a projected fracture area (ligament area) of 46,000 mm 2 (367.5 mm long by 125 mm wide), are analyzed. Through this technique, a microphotograph is taken and stored as a binary image using an image analyzer equipped with a stereo-microscope. The result is a topographical map of the fracture surface. Since the elevation of each point on the fracture surface is defined by its intensity value, the need for actual sectioning through the fracture surface, often employed, is eliminated. One-dimensional Fourier spectral analysis (1D FFT) to estimate the fractal dimension is carried out. To check the method of analysis, synthetic profiles with a known fractal dimension are generated. The results of the analysis suggest that concrete fracture surfaces are fractal for the range of scales considered, the digitized fracture surface images are found to mimic the actual fracture surfaces, their spectra follow a power lower behavior, and the technique is very promising and suitable for such materials.
10.14359/4585
SP143-17
A. Scanlon, A. Nanni, and S. Ragan
Describes a large-scale pendulum device for testing reinforced concrete structures under impact loading. Details of the facility, including instrumentation of specimens and pendulum mass, are provided. Sample test results relative to full-scale bridge barriers and beams are presented. These tests show differences between responses under static and dynamic loads.
10.14359/4586
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